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Engine/Cam Breakin

9.5K views 59 replies 13 participants last post by  Coletrane  
#1 ·
I'm building a fresh 350 and should be done in about a week as long as my parts arrive. As far as the breakin I was going to break in the cam based on the instructions by edelbrock, but they didnt specify anything about engine oil during breakin. As far as the rings go, I have moly faced rings and the college I had machine it for me knew that I was using these rings and told me that they would put a fine plateau finish on the cylinders and said that they should seat during cam breakin or very shortly after. Everyone, I have talked to said to use straight 30 until the rings seat, but Im worried that since its so thick and I need this engine in the truck in the next month that temps will be around 40 degrees and I dont want to starve the cam of oil.
 
#3 ·
break in

ok, now im confussed. i been reading all the little "similar search" stuff on the bottom of posts, breaking in a cam..........well, i got a completely rebuilt engine, scueduled to fire in a week or so, do i gotta rev it above 2000rpm as well with my application? for the cam break in? or is that for a guy only installing a cam?
 
#4 ·
That's the way to break in a cam. If you don't pre-oil the new engine. fire it up to idle speed until you get good oil pressure, look for any leaks, then run it at 2000rpm for 20 min or more. 30w is not as "thick" as you think. after your break in period, drain the oil and put in what you want. I would also buy an anti drainback filter (from Napa) that will help build oil pressure faster on cold start's. One would want to change the oil after break-in anyway to get rid of any break-in junk the filter catches on initial startup. :thumbup:
 
#6 ·
Rotellia diesel oil and a cam break in supplement change oil right after the 20 min cam breaking in using cheap dino oil and a good napa or wix filter ,then change oil at 500 miles and no synthetic until about 1500 miles moly rings will take a little while to fully break in.
 
#7 ·
jmichaelre said:
Is it necessary to use a breakin oil other than what is provided by the cam mfg? Seems odd to me to throw in a $15 bottle of additive to run 30 minutes and drain out, or should I add that stuff after the cam breakin?

yes! it is very necessary. those 30 minutes are the most important 30 minutes that engine will run. Don't be cheap, use the additive on every oil change. If you can't afford it, take a bus.
 
#9 ·
I understand, but oil is the blood of an engine, its VERY important. people will not hesitate to drop over $200 on an intake but won't spend the extra money for good rings, bolts, bearings, and oil- all of which are way MORE important for an engine than upgrading from a Torker intake to a RPM.
 
#11 · (Edited)
The following list of do's and don't's didn't sit well with the troops when I posted it originally, but if it helps even one person to prevent mushin' a cam, it's worth it. I even posted a disclaimer at the top to satisfy some of the members of this board.....

DISCLAIMER: THE FOLLOWING INFORMATION WAS GLEANED FROM MANY DIFFERENT SOURCES. SOME OF IT MAKES SENSE TO ME AND SOME OF IT DOESN'T. USE WHAT YOU THINK IS REAL AND THROW OUT THE REST OF IT. I HAVE NOT USED ALL OF THE SUGGESTIONS LISTED HERE. THROUGH THE YEARS, I HAVE ACCOMPLISHED MANY SUCCESSFUL FLAT TAPPET CAMSHAFT BREAK-INS, BUT I HAVE ALSO ROACHED A FEW. USE THIS LIST AS A GUIDELINE SO THAT YOU REMEMBER TO CHECK ALL THESE THINGS WHEN INSTALLING A NEW FLAT TAPPET CAMSHAFT. DO NOT TAKE EVERYTHING POSTED HERE AS GOSPEL. IF THE MANUFACTURER OF THE CAMSHAFT YOU'RE USING RECOMMENDS PROCEDURES THAT DIFFER FROM WHAT IS SHOWN HERE, USE THE MANUFACTURER'S RECOMMENDATIONS AND DISREGARD THIS INFORMATION.

Mistakes that may "frag" a flat-tappet camshaft and lifters.

1. Failure to remove all rust-preventative from cam and lifters with solvent once you get them home. (This advice does not include removing coatings applied at the factory such as phosphates. It is only suggesting to remove rust-preventative grease that may or may not have been applied to the cam/lifters to prevent rust in storage. This grease will not have the extreme pressure characteristics that Molybdenum Disulphide has and should be removed so that MD can be applied properly. MD is the black, tar-like extreme-pressure grease that is recommended by some camshaft manufacturers to be applied to the lifter crowns/cam lobes for initial camshaft break-in).

2. Failure to wash the cam and lifters with hot soapy water to remove the remainder of rust-preventative not removed with solvent. CAUTION; WASH ONLY THE CROWN OF THE LIFTERS. (THE VERY BOTTOM OF THE LIFTER WHERE IT CONTACTS THE CAMSHAFT LOBE). DO NOT ALLOW WATER TO GET INTO THE INTERIOR OF THE LIFTER BODY. BE VERY CAREFUL HERE IF THE LIFTER HAS AN OILING HOLE THAT HAS BEEN EDM'D INTO THE CROWN TO PROVIDE OIL FROM THE INTERIOR OF THE LIFTER BODY TO THE CAMSHAFT LOBE. Dry the cam and lifter crowns thoroughly with hot air from a hot air gun or hair dryer to remove all traces of moisture before applying Molybdenum Disulfide.
WARNING: DO NOT USE ANY ABRASIVE MATERIALS SUCH AS SCOTCHBRITE PADS OR SANDPAPER OF ANY KIND TO ACCOMPLISH THESE SOLVENT AND SOAP CLEANING OPERATIONS. USE ONLY SOFT, CLEAN RAGS. THE WHOLE INTENT OF CLEANING THE CAMSHAFT IS SO THAT WE CAN REMOVE RUST-PREVENTATIVE OILS AND GREASES THAT MIGHT HINDER GETTING DOWN TO THE BASE METAL IN ORDER TO PERFORM OPERATION #3 SHOWN HERE.

3. Failure to properly massage an extreme pressure lubricant such as Molybdenum Disulfide into the pores of the metal on all lobes and lifter faces. Moly will actually bond with the metal and give maximum protection to the lifter crown/lobe.

4. Failure to use an extreme pressure lubricant additive in the engine oil for camshaft break-in. Each cam grinder has his own specific product to facilitate valid cam break-in.

5. Failure to use the proper valve springs for cam break-in. You can't use the 300 lb over-the-nose springs that you'll eventually use in the motor and expect the cam to live at break-in. Assemble the heads with stock or weak single springs to break in the cam, then use one of the many tools available to change the springs with the heads on the motor. Alternately, assemble the heads with the springs you will run and use reduced-ratio break-in rockers, then change out the rockers after break-in. These rockers are available from Crower in different ratios for different motors. A popular ratio for a small block Chevy would be a 1.3:1 rocker. In other words, let's say the lift at the cam is 0.350" and the theoretical lift at the valve with 1.5:1 rockers is 0.525". Using the 1.3:1 rockers would result in lift at the valve of only 0.455", thus reducing stress at the camshaft/lifter interface during the crucial break-in period.

6. Failure to check for valve spring coil bind at max lift. If you cannot tell by eye, verify by inserting a .010- inch feeler gauge between the coils. A .010 space between five coils would give a total of .050 safety margin before stacking solid. If you cannot pass the feeler gauge between the coils, the spring is either coil bound or dangerously close to this condition, and you have probably overshimmed the spring (the fitted dimension is too short).

7. Failure to check for retainer to valve guide/seal clearance. 1/16"-1/8" clearance at full valve lift is considered sufficient.

8. Failure to check for binding at the rocker/stud interface with stamped steel rockers. Long slot rockers are made specifically to cure this problem.

9. Failure to check for piston/valve clearance..... 0.080" on the intake and 0.100" on the exhaust is considered by many to be the minimum clearance acceptable. You will probably find the closest near-miss at the exhaust valve on overlap, when the piston is chasing the exhaust valve back onto its seat.

10. Failure to run the motor at high rpms (2500 or higher, alternating 500/1000 rpm's up and/or down to allow the crank to throw oil in different places at different revs) for the first 40-45 minutes of its life. NO IDLING. NO IDLING. NO IDLING. The motor should not be run at less than 2500 rpm's for a minimum of 40 minutes. If a problem develops, shut the motor down and fix it, then resume break-in. The main source of camshaft lubrication is oil thrown off the crankshaft at speed, drainback from the oil rings and oil vapors circulating in the crankcase. At idle, the crank isn't spinning fast enough to provide sufficient oil splash to the camshaft/lifters for proper break-in protection.

11. Failure to clearance lifters in their bores so that they spin freely. Lifter clearance should be 0.0012" to 0.002", with 0.0015" (one and one/half thousandths) considered close to ideal. Too loose is as bad as too tight.

12. Failure to initially adjust the valves properly. Using the "spin the pushrod until it feels tight" method will normally result in valves too tight. Holding the rocker arm tip down against the valve stem tip with one hand, jiggle the pushrod up and down with your thumb/forefinger of your other hand until all play is removed, then turn the rocker nut 1/2 to 3/4 turn to set the preload. Builders who have done hundreds of engine builds may have the "feel" to do the "twist" method, but those fellows who are doing their first few builds lack the experience to do this and will have better results with the "jiggle" method.

13. Failure to inspect the distributor drive gear for wear. Too much wear can allow the cam to walk in its cam bore and contact an adjacent lifter.

14. Failure to have everything ready for the motor to fire on the first few turns. Fully charged battery, good starter, known-good carburetor with full fuel bowl, source of fuel to the carburetor to allow minimum 40 minutes of uninterrupted running. Ignition timing set. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER.

15. Failure to prime the oiling system prior to firing the motor. Prime until you get oil out of the top of each and every pushrod. Observe the oil pressure gauge to be sure pressure is registering. Priming will aid lubing the valvetrain at initial startup. It's the last area of the motor to get lubed on dry start.

16. Failure to use new lifters on a used cam. Used lifters should only be used on the very same cam, in the very same block and in the very same positions they were removed from. Chances that the lifter bores will be machined on the very same angles on a different block as the block the lifters came out of are about equal to you hitting the lottery.

Now, this last bit of advice comes from Racer Brown, world-renowned camshaft manufacturer/engineer who ground the hot cams for Chrysler Corporation during the horsepower wars of the 60's.
"Overfill the crankcase by at least 4 or 5 quarts of oil so that the oil level comes to within an inch of the top of the oil pan. Install a set of fairly hot spark plugs with a gap of 0.050" to 0.060" to prevent oil-fouling of the plugs, which is otherwise inevitable under no-load conditions with all the extra oil aboard. During this operation, we want near-maximum oil flow, together with a maximum of oil vapors and liquid oil thrashing about in the crankcase so that the cam lobe and lifter interface lubrication is considerably better than marginal."

This advice from the Racer is too scary for me, but I included it so that you know someone, somewhere has done it.

Just a note to make you aware of the loading between the camshaft lobe and lifter crown. That pencil-point of contact, if carried out to a square inch, would be somewhere between 250,000 and 300,000 POUNDS PER SQUARE INCH.
 
#12 ·
jmichaelre said:
I'm building a fresh 350 and should be done in about a week as long as my parts arrive. As far as the breakin I was going to break in the cam based on the instructions by edelbrock, but they didnt specify anything about engine oil during breakin. As far as the rings go, I have moly faced rings and the college I had machine it for me knew that I was using these rings and told me that they would put a fine plateau finish on the cylinders and said that they should seat during cam breakin or very shortly after. Everyone, I have talked to said to use straight 30 until the rings seat, but Im worried that since its so thick and I need this engine in the truck in the next month that temps will be around 40 degrees and I dont want to starve the cam of oil.
Straight 30 wt. non detergent oil is fine. Add a zinc additive for the initial break-in run if you have flat tappet lifters. If you are running rollers the additive is not required nor is the 20 minute break-in period.

The twenty minute break-in run should be done by starting the engine and bringing the RPM up to around 2000 right away. Idling the engine before the break-in run is completed can be detrimental. Vary the RPM from 2000-2500 every five minutes or so. Do not try to adjust the carb yet. Do check for leaks and shut down to fix as necessary. Watch the engine temperature and oil pressure. Check the total mechanical timing with the vacuum advance disconnected from the vacuum cannister and plugged at an RPM between 2500-3000. Set it between 32-38 degrees BTDC. This will prevent you from having the ignition retarded and causing your engine to run hot. An indication of retarded timing is if you see the exhaust pipes close to the exhaust manifolds getting cherry red, your timing is most likely retarded or you have a MAJOR vacuum leak causing you to run very lean.

Change the oil and the filter immediately after the twenty minute break-in. Change them again after the first 50, 100, 500 miles. After that, change the oil and filter after about 3000 miles. Do not use synthetic oil until you have around 2000 miles on the engine. Changing the filter is more important than changing the oil. Use a good filter. I suggest a NAPA (made for NAPA by WIX) or WIX oil filters.

The cam gets lubricated by 'splash'. This is why the engine RPM's are well above idle during the break-in run.

After the run is completed and the oil and filter have been changed; you can restart the engine and proceed with setting the timing and then adjusting the carb.
 
#13 · (Edited)
When installing new lifter's, I've ALWAYS soaked the lifter's covered with oil prior to install. Does anybody still do that? I haven't heard it mentioned yet. :confused: Old theory was to fill the lifter's so they would have oil in them while waiting for pressure from the pump. I believe it was called "priming the lifter's". yes? no? :confused:
As far as firing it up to 2000rpm right away, I'm going to make darn sure my gauge is showing 40 or more lbs of pressure before I take it up that far!
 
#14 ·
techinspector1 said:
The following list of do's and don't's didn't sit well with the troops when I posted it originally, but if it helps even one person to prevent mushin' a cam, it's worth it. 10. Failure to run the motor at high rpms (2500 or higher, alternating 500/1000 rpm's up and/or down to allow the crank to throw oil in different places at different revs) for the first 40-45 minutes of its life. NO IDLING. NO IDLING. NO IDLING. The motor should not be run at less than 2500 rpm's for a minimum of 40 minutes. If a problem develops, shut the motor down and fix it, then resume break-in. The main source of camshaft lubrication is oil thrown off the crankshaft at speed, drainback from the oil rings and oil vapors circulating in the crankcase. At idle, the crank isn't spinning fast enough to provide sufficient oil splash to the camshaft/lifters for proper break-in protection.


12. Failure to initially adjust the valves properly. Using the "spin the pushrod until it feels tight" method will normally result in valves too tight. Holding the rocker arm tip down against the valve stem tip with one hand, jiggle the pushrod up and down with your thumb/forefinger of your other hand until all play is removed, then turn the rocker nut 1/2 to 3/4 turn to set the preload. Builders who have done hundreds of engine builds may have the "feel" to do the "twist" method, but those fellows who are doing their first few builds lack the experience to do this and will have better results with the "jiggle" method.

14. Failure to have everything ready for the motor to fire on the first few turns. Fully charged battery, good starter, known-good carburetor with full fuel bowl, source of fuel to the carburetor to allow minimum 40 minutes of uninterrupted running. Ignition timing set. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER. NO GRINDING ON THE STARTER.

15. Failure to prime the oiling system prior to firing the motor. Prime until you get oil out of the top of each and every pushrod. Observe the oil pressure gauge to be sure pressure is registering. Priming will aid lubing the valvetrain at initial startup. It's the last area of the motor to get lubed on dry start.

16. Failure to use new lifters on a used cam. Used lifters should only be used on the very same cam, in the very same block and in the very same positions they were removed from.
All of the suggestions are excellent except the Racer Brown comment. The above suggestions are extremely important.
 
#15 ·
sqzbox said:
When installing new lifter's, I've ALWAYS soaked the lifter's covered with oil prior to install. Does anybody still do that? I haven't heard it mentioned yet. :confused: Old theory was to fill the lifter's so they would have oil in them while waiting for pressure from the pump. I believe it was called "priming the lifter's". yes? no? :confused:
As far as firing it up to 2000rpm right away, I'm going to make darn sure my gauge is showing 40 or more lbs of pressure before I take it up that far!
Not necessary. The lifters will get pumped up either when the oil pump is primed or as soon as the engine is turned over.

Assembly lube should be applied to the face of the lifters when they are installed and also to the tips of the pushrods.
 
#16 ·
sqzbox said:
When installing new lifter's, I've ALWAYS soaked the lifter's covered with oil prior to install. Does anybody still do that? I haven't heard it mentioned yet. :confused: Old theory was to fill the lifter's so they would have oil in them while waiting for pressure from the pump. I believe it was called "priming the lifter's". yes? no? :confused:
As far as firing it up to 2000rpm right away, I'm going to make darn sure my gauge is showing 40 or more lbs of pressure before I take it up that far!
These instructions are from Rhoads Lifters....
"Before installation, each Rhoads Lifter should be fully filled with oil. To fill with oil, completely submerge each lifter upright into a container of oil and compress the inner plunger with a pushrod or screwdriver until the plunger is driven to the bottom of the lifter. Hold several seconds and release slowly. Repeat several times until the lifter is fully filled. NOTE: Soaking lifters in oil will not fill them. Also, make sure to apply assembly lube to each cam lobe and lifter bottom."
 
#17 ·
I kind of feel sorry for this guy. After all this, his gut's are going to be turning the first time he start's it! :eek: I think you need to sit down and make your own list while reading this thread of what you want to do and what procedure so you won't be confused trying to remember. It's easier to check off thing's in order than rely on memory! :D
 
#22 ·
jmichaelre said:
Thanks for all the good responses, I just picked up the crank and bearings and I crabbed two bottles of breakin oil, one for the inital run and one for the for the fresh oil right afterwards.
I'm sure you know this, but for the benefit of others reading this thread, all this monkey-motion break-in foolishness can be circumvented by using roller lifters. You just wash them with solvent, oil them, put them in, crank the motor and drive.
 
#23 ·
I'm not getting really paranoid on this one i've just had problems in the past. Two years ago I tore down an engine and only had money for bearings, rings, camshaft and timing chain. That motor gave me problems the whole time. I'll never just do just a rering job again. Going through all of this one I've had everything checked out and machined and I have more piece of mind that it'll work out. The only good thing I can say is with all the problems I had with the other one, it gave me a lot of hands on tuning and diagnosing problems and knowing what things should and shouldnt do when running correctly.
 
#24 ·
A roller setup would be sweet, but this project wouldn't fully utilize I don't think. Especially since I can't afford new heads right now. Though I have smaller heads, everything has been gone through and should be pretty reliable, but I do look forward to working on something down the road that uses a roller setup and is made for speed. But right now this is going into my 4x4 work horse.
 
#25 ·
Again, for others reading this, if you are just in the planning stages of a 350 or 383 Gen I build, for heaven's sake make plans to begin with a roller tappet block, such as the L31 5700 from a '96-'99 Chevy truck. You can, in most cases, re-use the stock lifters if you limit valve lift to around 0.525". If you use much more cam than that, you can pop the lifters out of their bores. But for a street or street/strip motor (+/- 6000 rpm's), it just makes sense to begin with a roller block.

In the past few months, I have seen 2 rebuildable short blocks on craigslist here in Phoenix for under 200 bucks, including lifters, dog bones and spider.